<?php
//划分成绩段
    function x($score = 46){
    	switch(floor($score/10)){
    		case 10:
    		case  9:  $grade = 'A'; break;
    		case  8:
    		case  7:
    		case  6:  $grade = 'B'; break;
    		case  5:
    		case  4:
    		case  3:
    		case  2:
    		case  1:
    		case  0:  $grade = 'c'; break;
    	}
    	echo $grade;

    }

    x();
    ?>

    